1. Field of the Invention
The present invention relates to moldable/extrudable thermotropic aromatic copolyesteramides and to the preparation thereof from at least one substituted hydroquinone, or ester/amide-forming derivative thereof, from a mixture of aromatic dicarboxylic acids, or ester/amideforming derivatives thereof, and from at least one aromatic aminocarboxylic acid, or ester/amide-forming derivative thereof.
2. Description of the Prior Art
Thermotropic polyesters prepared from one or more diphenols and one or more aromatic and/or alicyclic dicarboxylic acids are known to this art. Polyesters of this type are described, for example, in French Pat. No. 2,270,282. Among the polyesters described therein, those produced from a substituted hydroquinone (or ester-forming derivative thereof), terephthalic acid (or ester-forming derivative thereof) and 4,4'-dicarboxydiphenyl ether (or ester-forming derivative thereof) are valuable polymers. Because of the high price of the raw materials for such polymers, it would be desirable to replace a portion of the most expensive reagents, namely, substituted hydroquinone (or derivative thereof) and 4,4'-dicarboxydiphenyl ether (or derivative thereof) by a less expensive compound that is readily commercially available. Moreover, these particular copolyesters have inadequate thermomechanical properties. In particular, their torsional moduli at high temperatures need to be improved.